This is presented about in my homemalin township trip experience. In this areas are the mostly placer type and so they are made hydraulic mining methods. Two types of hydraulic mining methods are used. They are land and water sluicing.Land sluicing is made the high pressure of water to spray to the land hill which contents gold with gravel pump and then the sucking mixed ores with gravel and water collected into the small pit. The mixed ores are lifted up with 185-290 hp engines and after passed through the sluice box with covered canvas. The length of sluice box is 20- 80 ft long and the width is 5-10 ft wide.The slope of sluice box is 15-30 degree variables state to control the water flow rate. The water sluicing is also made with the raft on water. And also another steps are the same as the land sluicing. The canvas are also covered with one canvas overlapping to another to control the water flow rate and collected the gold ores particles. So I think that we have to get more gold, we need to make right design and modernize technique. Mainly we can make to control the water flow rate.
In my suggestions, advisings and opinions about this are needed to make the right slope to control water flow rate.If you do not control the water flow rate, you will not get the more gold. And also I want to make the wooden riffles are placed the definite distance between the canvas. More control water flow rate and more settle the gold ores particles.
This paper is not included how to make amalgam, sponge gold and recover mercury. So I write to continue the about of above case .